In your example, you have a19 in the numerator and a10 in the denominator. Exponents with a value equal to or greater than 10 are displayed incorrectly.
To properly display the exponents, enclose them with curly brackets. The following equation will display correctly:
To properly display the exponents, enclose them with curly brackets. The following equation will display correctly:
\(\large{ \dfrac{{a}^{{n1}}\times {a}^{{n2}}}{{a}^{{n3}}\times {a}^{{n4}}} = {a}}\)